Open fan aircraft engines equipped with contra-rotating propulsor systems continue to generate interest in the aviation industry, particularly as fuel prices increase, due to the efficiency of contra-rotating open fan aircraft engines. Contra-rotating propulsor systems are of particular interest due to their efficiency and ability to generate adequate thrust at high speed.
Based on previous experience in the industry, the effective perceived noise levels generated by contra-rotating propulsors exceed noise thresholds set by regulatory agencies for aircraft, which renders use of contra-rotating engine systems for commercial applications problematic. Accordingly, techniques to address the reduction of noise levels in contra-rotating engine systems may find utility.